Compressor unloader



March 17, 1936. c. E. PLOEGER COMPRESSOR UNLOADER Filed April 28, 1931 3 Sheets-Sheet l INVENTOR. C. 5 PLOEGER March 17, 1936. c. E. PLOEGER COMPRESSOR UNLOADER Filed April 28, 1931 5 Sheets-Sheet 2 mm 6. E VE m m V. B

A TTORNE March 17, 1936.

c. E. PLOEGER 2,034,153

COMPRES S OR UNLOADER Filed April 28, 1931 3 Sheets-Sheet 3 INVENTOR.

BY C. E PLOEGER ATTONEY Patented Mar. 17, 1936 UNITED STATES 2,034,153 COMPRESSOR UNLOADER Clyde E. Ploeger, Evansville, Ind., assignor to Servel Inc., New York, N. Y., a corporation of Delaware Application-April 2a, 1931, Serial No. 533,441

16 Claims.

This invention relates to unloaders and more particularly to an unloadervalve for the compressor of a refrigerating machine.

An object of this invention is to provide an automatic valve arrangement for equalizing the pressures on both sides of a compressor at starting.

Another object is to automatically close the compressor suction line when the equalizing connection is open. g

Other objects and advantages will be apparen from the following description taken in connec-- tion with the accompanying drawings, in which Figure 1 is an elevation partly in vertical secthis invention;

Figure 2, a view similar tothat of Figure 1 but at right angles thereto; Figure 3, a detail section taken on line 33 of Figure 1; and

Figure 4, a detail view partly in vertical section showing the valve arrangement shown inelevation in Figure 2. 3

Referring to Figures 1 and 2. of the drawingsa compressor [0 is driven by a vertical electric motor ll through an eccentric crank'l2 and yoke I3, to which latter the piston of the compressor I0 is attached. The compressor and motor are mounted as a unit on a frame l4 supported by upwardly extending lugs I5 in a crank case l6 adapted to cooperate with and fit into recesses H in --the frame M, the recesses being lined with sound 35 deadening material l8. A dome or cover 9 provided with heat radiating fins 26 is secured to the crank case I6 by a retaining ring or lugs 2| and bolts 22 to form a fluid tight casing around the unit. Electrical connections to themotor are 40 made through the crank case by means of terminals in fluid tight insulating bushings 23 of dielectric material.

The compressorshown more in detail in Figure 3 includes a cylinder 24 removably mounted in the extension 25 of the frame l4 and held in place by the valve plate 26 which is fastened to the frame extension by stud bolts 21. The intake of the compressor from the-evaporator, not shown, 0 is through pipe 28, the intake conduits in plate 26, and a resilient flap intake vvalve 52. The

compressor discharges through a discharge valve inafter described, and connection is. made from tion of a motor compressor unit for refrigerating apparatus embodying a Y valve contemplated by the interior of the casing to the condenser, not shown, through pipe 3|, as shown in Figure 2.

Referring to Figure 4, a casing 32 encloses a chamber 33 which communicates with the compressed gas space enclosed by the unit casing 5 through ports 34 and 35. The compressor discharge pipe 39 is connected to the top of the chamber 33. Adapted to "reciprocate in the chamber 33 is a piston 36-composed of an upper member 31 and a lower member 38, the latter fit- 10 tinginto a recess in the bottom of the former. The piston 36 is made in two parts to'allowfor' assembly of the valve stem 39 and spring 40. The two members 3'! and 38, of piston 36 operate together as a unit and it will be understood that .15 piston 36 may comprise asingle member.-

The valve stem 39 extending through an aper- I ture in the member 38 is operatively connected to member 31 by thespring and is adapted to open and close a port 4| which communicates 0 with the compressor intake through conduits 42, 43, and 44 in the valve plate 26. The piston 36 is urged upwardly. within the chamber 33 by a spring .45.

The compressor intake is through suction line 25' 28, conduits 44, 46, and 41 in the valve plate 26, and' the intake valve 52. A normally open check valve 48 is adapted to close the valve opening 49 in conduit 44 above its connection with the intake of the compressor through conduits 46 and 41. v When the compressor. is operating, vapor is drawn from the evaporator, not shown, through the suction line 28 and conduits 44, 46, and 41 in the valve plate 26. Compressed vapor is discharged through valve 56 in the casing 5| and pipe ,30' into chamber 33 in which the compressed gas holds the piston 36 down against the action of springs and and escapes into the space under 40 the unit casing through port 34 which is uncovered by the piston 36 in its lower position. In this position. the piston 36 also covers port 35 and maintains the valve stem 39 in a position to close port 4 I.

When the compressor stops, the pressure above the piston in chamber 33 is relieved through port 34 and the action of spring 45 raises the piston .36 uncovering port 35- and unseating the valve stem 39. Compressed gas entering port 35 passes 60 through port 4|, conduits '42, 43, and 44, raising the check valve 48 against its seat 4.9, thus preventing entrance .of compressed gas into thesuction line 28 :but allowing the gas to pass'through conduits 46 and 41 to the intake side of the com- The use of spring 40 insures closing of the port 4| by valve stem 39 before the port 34 is opened, which gives the device a dashpot effect and prevents chattering which Would otherwise occur due to the pulsating gas pressure.

It will be obvious to those skilled in the art that various changes may be made in the construction and arrangement without departing from the spirit of the invention andtherefore the invention is not limited to what is shown in the drawings and described in the specification but only as indicated in the following claims.

I claim:

1. Compressor unloading means including a fluid tight cylinder, a piston adapted to reciprocate within said cylinder, discharge connection from the compressor to one end of said cylinder, means to urge the piston toward this end of the cylinder, a port in said cylinder uncovered by said piston in its position away from the compressor discharge connection end of said cylinder, a second port uncovered by said piston in its position at the compressor. discharge connection end of said cylinder, a third port in the other end of said cylinder, means responsive to the movement of the piston for closing said third port when the piston moves toward the last said end of the cylinder and before the first said port is uncovered, an intake conduit to the low pressure side of the compressor, a connection from the low pressure side of the compressor to the third said port, and a check valve in said intake conduit adapted to close responsive to the pressure in said connection to the third said port when the latter is open.

2. Compressor unloading means including a fluid tight cylinder having one end connected to the high pressure side'of a compressor and having a flow restricting port therein, a piston reciprocable in said cylinder to close said port in its first position and open said port in its opposite position, means for urging said piston to its first position,a pressure equalizing connection from the high pressure to the low pressure side of the compressor, means operatively connected to said piston for opening and closing said connection responsive to the pressure on said piston, and means for closing the compressor intake line when said equalizing connection is open.

3. In combination with a compressor, a fluid tight cylinder connected at one end in series with the compressor discharge line, a pressure equalizing line to the intake side of the compressor, a piston reciprocable in said cylinder adapted to open and close said pressure equalizing connection, and means for closing the compressor intake line when said pressure equalizing connection is open.

4. Compressor unloading means comprising a flow restriction in the discharge line from the compressor, a check valve in the intake line to the compressor, and means for controlling communication between the high and low pressure sides of the compressor responsive to the pressure behind said restriction.

stricting means in the discharge line, a check valve in the intake line, a pressure equalizing connection between the low and-high pressure sides of the compressor, and means for opening and closing said connection responsive to the pressure behind said restricting means.

6. In combination with a compressor, a flow restriction in the discharge line, a pressure equalizing connection between the high and low pressure sides of the compressor, means for opening and closing said connection responsive to the pressure behind said restriction, and means for closing the compressor intake line when said pressure equalizing connection is open.

'7. Refrigerating apparatus including a casing enclosing a fluid tight chamber, a motor compressor unit mounted within said chamber, an

intake conduit to the compressor from without said casing, a closed cylinder within said chamber, a piston adapted to reciprocate within said cylinder, a discharge conduit from the compressor to one end of said cylinder, means to urge the piston toward this end of the cylinder, a fluid flow-restricting port in said cylinder uncovered by said piston when displaced against the action of said means, a pressure equalizing conduit from said intake conduit opening within said chamber, a valve in said pressure equalizing conduit, means for operating said valve responsive to the movement of said piston, and means for closing said intake conduit when said pressure equalizing conduit is open.

8. In combination, a container for compressed fluid, a compressor, a discharge conduit from said compressor to said container, fluid flow retarding means in said conduit, a compressor intake conduit, a check valve in said intake conduit, a pressure equalizing connection between said container and intake conduit, and means for closing said connection responsive to an increase in pressure in said discharge conduit between the compressor and said fiow retarding means.

..9. In combination, a container for compressed gas, a compressor within said container, a compressor discharge conduit opening within said container through a fluid flow retarding device, an intake conduit in said compressor from without said container, a check valve in said intake conduit, a pressure equalizing conduit from said intake conduit opening within said container, a valve in said pressure equalizing conduit, and means for operating said valve responsive to the pressure in said discharge conduit.

10. Refrigerating apparatus including a casing enclosing a fluid tight chamber, a compressor within said chamber, an intake conduit to said compressor extending through said casing, a check valve in said conduit, a compressor discharge conduit opening within said chamber through a fluid fiow restriction, a pressure equalizing conduit from said intake conduit opening within said chamber, and means for closing said pressure equalizing conduit responsive to an increase in pressure in said discharge conduit.

11. Refrigerating apparatus including a casing enclosing a fluid tight chamber, a motor-compressor unit mounted within said chamber, an intake conduit to the compressor from without said casing, a compressor discharge conduit opening into said chamber and having a fluid flow restriction, a pressure equalizing connection from said intake conduit into said chamber, means for closing said connection responsive to an increase in pressure in said discharge conduit, and means for closing said intake conduit when said connection is open,

12. In combination with a compressor connected to discharge into a container for compressed fluid, means for retarding the flow of fluid from the compressor to the container, a pressure equalizing connection from the container to the intake side of the compressor, and means for closing said connection responsive to the pressure difierence created by said flow retarding means when the compressor is operated.

13. In combination with a compressor, a fluid tight chamber connected with the compressor discharge line, a pressure equalizing line to the intake side of the compressor, means in said chamber adapted to open and close said pressure equalizing connection, and means for closing the compressor intake line when said pressure equalizing connection is open.

14. In combination with a compressor having pressure and suction lines, means providing a chamber in the pressure line having a flow restricting opening, a pressure equalizing connection between the pressure and suction lines, and means responsive to pressure in said chamber for controlling the pressure equalizing connection.

15. In a device of the class described, a pressure line, a suction line, flow restricting means in the pressure line, a check valve in the suction line, and means for controlling communication between the pressure and suction lines responsive to the pressure built up by the flow restricting means.

16. In a compressor, a conduit for flow of compressed fluid from the compressor having a portion'of reduced cross-sectional area for restricting flow of gas therethrough during operation of the compressor, means for relieving load on the compressor, and means to actuate the loadrelieving means in response to difierence in pressures on opposite sides of said portion of reduced crosssectional area, said actuating means being operative to relieve a load on the compressor below the compressor speed at which flow of compressed gas through said conduit is productive of a predetermined difierence in pressures on opposite sides of said reduced portion of said conduit.

CLYDE E. PLOEGER. 

